Infection of human T lymphocytes or T lymphocyte lines with the AIDS retrovirus (RV) can result in a variety of outcomes ranging from rapid cell death to the stable integration of functionally inert proviral DNA and no obvious viral cytopathic effect. A typical AIDS RV infection of CD4+ lymphocytes is characterized by the rapid appearance of multinucleated cells, a burst of reverse transcriptase activity and profound cellular degeneration that extends over a 5 to 20 day period. During the past year we have characterized CD4- cells that survive acute infection and which neither produce nor are infectable by the AIDS RV. Such "survivor" cells can be induced to produce infectious virus following treatment with 5-iodi-2'-deoxyuridine (IUdR). A cellular clone was isolated from a mass culture of survivor cells that contained a single copy of the AIDS RV provirus. The integrated proviral DNA was constitutively expressed but generated defectived virus particles that failed to synthesize reverse transcriptase. The biological and biochemical properties of this cloned survivor cell has been investigated with the goal of understanding the interaction of viral gene products involved in cell killing.